Crib is a bed used for infants and young children. In order to ensure the safety of the sleeping baby, the existing cribs cannot act as a cradle. Without the rhythm of rocking, the baby may cry and cannot fall asleep easily. The Chinese Patent Application No. CN201210289214.6 discloses a crib, the bottom of which can be either linear or arc-shaped so as to function as a stationary-type crib or a cradle-style crib, respectively. However, this crib cannot realize smooth and convenient switch between its two states.